DNA, Genes and Protein Synthesis

Question 1

What is DNA?

Answer 1

DNA holds genetic information

Question 2

What is RNA?

Answer 2

RNA transfers genetic information from DNA to the ribosomes

Question 3

What are ribosomes formed from?

Answer 3

RNA and proteins

Question 4

What is a nucleotide?

Answer 4

DNA and RNA are polymers of nucleotides. Each nucleotide is formed from a pentose, nitrogen containing organic base and a phosphate group.

Question 5

Describe the components of a DNA nucleotide

Answer 5

Deoxyribose, a phosphate group and one of the organic bases adenine, cytosine, guanine or thymine.

Question 6

Describe the components of an RNA nucleotide

Answer 6

Ribose, a phosphate group and one of the organic bases adenine, cytosine, guanine or uracil.

Question 7

What bond joins two nucleotides together?

Answer 7

Phosphodiester bond

Question 8

What is the difference between the polynucleotide chains of DNA and RNA?

Answer 8

A DNA molecule is a double helix with two polynucleotide chains held together by hydrogen bonds between specific complementary base pairs. An RNA molecule is a relatively short polynucleotide chain.

Question 9

What does semi-conservative replication of DNA ensure

Answer 9

Genetic continuity between generations of cells

Question 10

What does the process of semi-conservative replication involve?

Answer 10

1) DNA helicase causes strands to separate by breaking hydrogen bonds between them.
2) Both strands act as templates.
3) Free nucleotides attach via complementary base pairing.
4) Hydrogen bonds reform.
5) DNA polymerase joins nucleotides to the new strands by forming phosphodiester bonds
6) New DNA molecules contain one old and one new strand

Question 11

How is DNA found in prokaryotic cells?

Answer 11

DNA molecules are short, circular and not associated with proteins.

Question 12

How is DNA found in eukaryotic cells?

Answer 12

In the nucleus of eukaryotic cells, DNA molecules are very long, linear and associated with proteins called histones. Together a DNA molecule and its associated proteins form a chromosome.

Question 13

Which organelles in eukaryotic cells also contain DNA?

Answer 13

Mitochondria and chloroplasts

Question 14

What is a gene?

Answer 14

A base sequence of DNA that codes for the amino acid sequence of a polypeptide and a functional RNA (including rRNA and tRNA)

Question 15

What is a locus?

Answer 15

A gene occupies a fixed position, called a locus, on a particular DNA molecule

Question 16

What is a triplet?

Answer 16

A sequence of three DNA bases that code for a specific amino acid

Question 17

What is the genetic code described as being?

Answer 17

Universal, non-overlapping and degenerate

Question 18

What is an exon?

Answer 18

Section of base sequence that code for polypeptides

Question 19

What is an intron?

Answer 19

A non-coding multiple repeat of base sequences between genes

Question 20

What is a genome?

Answer 20

The complete set of genes in a cell

Question 21

What is a proteome?

Answer 21

The full range of proteins that a cell is able to produce

Question 22

What is a transcription?

Answer 22

Transcription is the production of mRNA from DNA. RNA polymerase joins mRNA nucleotides together. In prokaryotes transcription results directly in the production of mRNA from DNA. In eukaryotes, transcription results in the production of pre-mRNA which is then spliced to form mRNA.

Question 23

What is translation?

Answer 23

Translation is the production of polypeptides from the sequence of codons carried by mRNA.